Capacity Pallet Documentation Improvements (#1997)

# Goal
The goal of this PR is to improve the documentation of the Pallets and
make that documentation be able to be used on docs.frequency.xyz.

Part of frequency-chain/docs#59

# Discussion
- Capacity Pallet Readme

---------

Co-authored-by: V. Claire Olmstead <[email protected]>
Co-authored-by: Joe Caputo <[email protected]>

Author: 3 people

pallets/capacity/README.md

@@ -0,0 +1,63 @@
+# Capacity Pallet
+
+The Capacity Pallet manages the staking and balances for Capacity, an alternative payment system on Frequency.
+
+## Summary
+
+Capacity is an alternative to paying with tokens for a limited set of calls.
+These Capacity eligible extrinsics are noted in each pallet's documentation with "Capacity" in the Payment column of the extrinsics section.
+Tokens can be staked to generate Capacity for a targeted Provider.
+The generated Capacity renews each [Epoch](#capacity-epoch).
+[Learn more about Capacity](https://docs.frequency.xyz/Tokenomics/ProviderIncentives.html#capacity-model).
+
+### Staking & Unstaking
+Currently, the token to Capacity ratio is 50:1.
+For example, for a 5 token stake, a Provider would receive 0.1 Capacity.
+Staking and unstaking affect available Capacity immediately.
+
+### Capacity Epoch
+
+A Capacity Epoch is a period consisting of a specific number of blocks, during which a Provider's utilization of network Capacity is capped at the amount of generated Capacity targeted to that Provider.
+At the start of each new Epoch, the available Capacity is renewed for each Provider, regardless of how much they consumed in the prior Epoch.
+The duration of a Capacity Epoch is determined by Governance, and is currently set to 7200 blocks.
+With the current average block time of approximately 12 seconds, one Capacity Epoch lasts around 24 hours on Mainnet.
+
+### Thaw Period
+
+After unstaking, the tokens will still be frozen for a set amount of time before they are unencumbered and able to be transferred.
+The `UnstakingThawPeriod` constant defines the number of Epochs that must pass before the tokens may be reclaimed for any use via `withdrawUnstaked()`.
+Currently it is set to 30 Epochs or ~30 days after unstaking.
+
+### Actions
+
+The Capacity Pallet provides for:
+
+- Staking to receive Capacity
+- Unstaking & Thaw Period
+- Capacity Epoch management
+
+## Interactions
+
+### Extrinsics
+
+| Name/Description                 | Caller        | Payment | Key Events                                                                                                    | Runtime Added |
+| -------------------------------- | ------------- | ------- | ------------------------------------------------------------------------------------------------------------- | ------------- |
+| `stake`<br />Lock tokens to grant Capacity to a Provider | Token Account | Tokens | [`Staked`](https://frequency-chain.github.io/frequency/pallet_capacity/pallet/enum.Event.html#variant.Staked) | 1             |
+| `unstake`<br />Begin the process of unlocking tokens by unstaking currently staked tokens | Token Account | Tokens | [`UnStaked`](https://frequency-chain.github.io/frequency/pallet_capacity/pallet/enum.Event.html#variant.UnStaked) | 1             |
+| `withdraw_unstaked`<br />Complete the process of unlocking tokens staked by releasing locks on expired unlock chunks | Token Account | Tokens | [`StakeWithdrawn`](https://frequency-chain.github.io/frequency/pallet_capacity/pallet/enum.Event.html#variant.StakeWithdrawn) | 1             |
+
+See [Rust Docs](https://frequency-chain.github.io/frequency/pallet_capacity/pallet/struct.Pallet.html) for more details.
+
+### State Queries
+
+| Name      | Description         | Query                    | Runtime Added |
+| --------- | ------------------- | ------------------------ | ------------- |
+| Get Capacity Ledger | Returns the Capacity balance details for a Provider's MSA Id  | `capacityLedger` | 1             |
+| Get Current Epoch | Returns the current Capacity Epoch number  | `currentEpoch` | 1             |
+| Get Current Epoch Info | Returns information about the current Capacity Epoch such as the starting block number | `currentEpochInfo` | 1             |
+| Get Staking Account Ledger | Returns information about an account's current staking details | `stakingAccountLedger` | 1             |
+| Staking Target Ledger | Returns information about an account's current staking details for a specific target Provider MSA Id | `stakingTargetLedger` | 1             |
+| Get Unstake Information | Returns the information about an account's current unstaking details and the unlocking chunks | `unstakeUnlocks` | 1             |
+
+
+See the [Rust Docs](https://frequency-chain.github.io/frequency/pallet_capacity/pallet/storage_types/index.html) for additional state queries and details.

pallets/capacity/src/lib.rs

@@ -1,41 +1,19 @@
-//! # Capacity Pallet
-//! The Capacity pallet provides functionality for staking tokens to the Frequency network.
+//! Managages staking to the network for Capacity
 //!
+//! ## Quick Links
 //! - [Configuration: `Config`](Config)
 //! - [Extrinsics: `Call`](Call)
 //! - [Event Enum: `Event`](Event)
 //! - [Error Enum: `Error`](Error)
+#![doc = include_str!("../README.md")]
 //!
-//! ## Overview
-//! Capacity is a refillable resource that can be used to make transactions on the network.
-//! Tokens may be staked to the network targeting a provider MSA account to which the network will grant Capacity.
+//! ## Lazy Capacity Refill
 //!
-//! The network generates Capacity based on a Capacity-generating function that considers usage and network congestion.
-//! When token is staked, the targeted provider MSA receives the Capacity generated.
-//!
-//! This Capacity can be used to pay for transactions given that the key used to pay for those transactions have a minimum balance
-//! of the existential deposit.
-//!
-//! The staked amount may be increased, targeting either the same or a different target to receive the newly generated Capacity.
-//! As a result, every time the network is staked to, the staked tokens are locked until unstaked.
-//!
-//! Unstaking schedules some amount of token to be unlocked. Any amount up to the total staked amount may
-//! be unstaked, however, there is a a limit on how many concurrently scheduled unstaking requests can exist.
-//! After scheduling tokens to be unlocked, they must undergo a thaw period before being withdrawn.
-//!
-//! After thawing, the tokens may be withdrawn using the withdraw_unstaked extrinsic.
-//! On success, the tokens are unlocked and free up space to submit more unstaking request.
-//!
-//! The Capacity pallet provides functions for:
-//!
-//! - staking and, updating,
-//!
-//! ## Terminology
-//! * **Capacity:** A refillable and non-transferable resource that can be used to pay for transactions on the network.
-//! * **Staker:** An account that stakes tokens to the Frequency network in exchange for Capacity.
-//! * **Target** A provider MSA account that receives Capacity.
-//! * **Epoch Period:** The length of an epoch in blocks, used for replenishment and thawing.
-//! * **Replenishable:**  The ability of a provider MSA account to be refilled with Capacity after an epoch period.
+//! Capacity is refilled on an as needed basis.
+//! Thus, the provider's capacity balance retains the information of the last epoch.
+//! Upon use, if the last Epoch is less than the current Epoch, the balance is assumed to be the maximum as the reload "has" happened.
+//! Thus, the first use of Capacity in an Epoch will update the last Epoch number to match the current Epoch.
+//! If a provider does not use any Capacity in an Epoch, the provider's capacity balance information is never updated for that Epoch.
 //!
 // Substrate macros are tripping the clippy::expect_used lint.
 #![allow(clippy::expect_used)]